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Space: U.S. Considers Asteroids A Real Threat To Earth

  • Julie Moffett

Washington, 27 May 1998 (RFE/RL) -- Asteroid and meteorite collisions with Earth are staples of science fiction and Hollywood, but the U.S. is taking the threat seriously.

So seriously, in fact, that the U.S. Defense Department has been working with the National Aeronautics and Space Administration (NASA) on a special program since early 1997 to track comets, asteroids and other assorted cosmic debris in an attempt to improve the ability to forecast a collision with Earth.

The program called the "Near-Earth Asteroid Tracking Program" (NEAT) is run by U.S. scientists, astronomers, physicists, and other military and civilian personnel.

Steve Pravdo, a project manager for NEAT at NASA's Jet Propulsion Laboratory in California, told RFE/RL that since the program's inception, they've been able to chart and track a fairly large number of cosmic objects.

According to Pravdo, the program's super-sensitive telescopes have already detected more than 25,000 objects, including 30 near-Earth asteroids and two long-period comets.

Asteroids are considered relics of the formation of the early solar system. Most of them are composed of rocky material made up of nickel and iron. They can range in size from a small boulder to the largest asteroid belt called Ceres, which is approximately 965 kilometers in diameter.

A comet is a body of ice with embedded rock or organic material which explodes and spews gases and dust as it approaches the Sun. A long-period comet travels vast distances, usually from a region far beyond the most distant planet in the solar system, Pluto, and can suddenly appear unannounced.

NASA officials say their goal is to track at least 90 percent of the near-Earth objects within the next 10 to 15 years. But last year, the agency was only able to track about 7 percent of the objects they were looking for due to budget constraints.

Pravdo says that unfortunately, NEAT's telescopes are currently monitoring the sky only six days a month, starting six nights prior to the new moon. He says this is the "absolute minimum" required to keep the program going.

This lack of progress has made many in the U.S. Congress angry. Just last week a congressional panel summoned astronomers and NASA officials to testify on real-life asteroid threats and ensure that enough was being done to protect Earth from such cosmic dangers.

The topic is also a hot one among the American public as well. Hollywood is producing two summer adventure films that feature threats to the Earth from runaway asteroids.

But NASA insists it is renewing its focus on the program. The agency recently doubled its annual funding of NEAT -- and will now spend three million dollars on the project. Officials also say they are launching additional space probes to study the characteristics and composition of asteroids and comets -- research that would be critical if someday they needed to be deflected from Earth.

Additionally, NASA recently added a new, state-of-the-art computer, two hi-tech cameras and improved data analysis hardware to the program.

Pravdo says the new equipment will dramatically improve the program's ability to track more asteroids.

Says Pravdo: "We will be able to double the amount of sky we search each night, which is currently 500 square degrees, as well as the number of new asteroids and comets we find during each monthly observation cycle."

But Pravdo says that even with the improved advanced tracking system, an asteroid or comet could slam into Earth at any time without warning. Explains Pravdo: "It is 100 percent likely it will happen. It has happened, it continues to happen, and it happens every day.... It is just a question of what size."

Pravdo says if a small asteroid about one kilometer long slammed into one of Earth's oceans, it could create enormous tidal waves that would completely wipe out most small islands and many nearby coastal cities.

A asteroid ten times that size, he says, would be considered an "extinction event," or the end of most human and animal life on the planet.

Such an impact, Pravdo explains, would cause a dust storm that could block out the sun for years, causing uninhabitable conditions on Earth and basically wiping out global agriculture. He says many scientists believe this is exactly the scenario that forced the dinosaurs into extinction.

But Pravdo says he remains optimistic about the future of the program and is glad to be a part of it.

He adds: "I'm very pleased about all we've been able to accomplish on a very low budget and a short amount of time on the telescope."